Sanctification, or in its verbal form, sanctify, literally means "to set apart" for special use or purpose, that is, to make holy or sacred. Therefore, sanctification refers to the state or process of being set apart, i.e. made holy.
It is quite true that sanctification and justification should not be sundered, but rather kept in the closest of relations to one another. But this does not mean that we are to confuse the one with the other. If a man is truly justified by faith, then that faith will surely lead him in the power of God to a new life, and the one experience may well held to imply the other. But that is not the same as saying that the two experiences are in the essence the same. Though in practice they may go together, yet for purposes of discussion they may be considered separately, and justification is the name given in the Bible tot he changed status, not the changed nature. (Morris, Leon. The Apostolic Preaching of the Cross. Grand Rapids: Eerdmans, 1965. Print. 291)